Someone on the Well Trained Mind Forums (where I've been spending way too much time lately) posted a poll asking whether conservatives thought that people were basically good or bad - it generated a lot of responses. Here's what I said:
Don't have time to read through all the responses, but I think the question is basically flawed...as are people! :) But since you asked...
I believe we're born with an inherent selfishness that causes us to rebel, but at the same time, we were made perfect in the image of our Creator. So to be fully human is actually to be totally good, but we won't get there until God restores his creation when Jesus returns. Meanwhile, we can be born again, whereby we still live with our sinful nature, but it doesn't rule us once we are submitting ourselves to the Holy Spirit. So we still "do what we do not want to do" (the apostle Paul's words) but our response to God's grace (unmerited favor from an unobligated giver) is a desire to love him and thus obey him, in thankfulness and knowing that his ways are the best.
There's also common grace, which is what keeps us all from destroying each other and the planet. So even those that reject the gospel, which is God's mercy and grace (Jesus atoning for our sins and reconciling us to the Father by becoming the perfect sacrifice to satisfy God's perfect nature which demands justice for wrongdoing, no matter how seemingly trivial to us), still bear the image of their creator and have his truths written on their hearts, so they are capable and inclined toward doing good more than evil, but it is a slippery slope without Christ, whereby anyone is able to be dragged down to the depths of their sinful nature, especially with their vulnerability to the deception presented by the devil whom they usually don't believe in, and therefore oblivious to his schemes (see The Screwtape Letters by C.S. Lewis).
Btw, I don't consider myself conservative or liberal - it all depends on the individual issue. I'm solidly pro-life (no abortion or CP). I voted for Ron Paul and would again, though I don't agree with all his views - it's more his character that made me vote for him.